Pipe bending machine and bending method

Abstract

The invention relates to a pipe bending machine and a bending method, and belongs to the technical field of bending machines, the pipe bending machine comprises a machine body and a rotary motion mechanism, the rotary motion mechanism is connected with a pipe bending eccentric die and a clamping die mechanism, the pipe bending eccentric die and the clamping die mechanism are oppositely arranged, one side of the clamping die mechanism is provided with an auxiliary pushing and guiding die mechanism, and the other side of the clamping die mechanism is provided with an auxiliary pushing and guiding die mechanism. The clamping die mechanism and the auxiliary pushing and guiding die mechanism are sequentially arranged in the length direction of the machine body; the pipe bending eccentric die comprises an eccentric wheel die body which is an eccentric fan-shaped disc, the center position of the eccentric wheel die body deviates from the rotating center of the eccentric wheel die body, and an upper wheel die and a lower wheel die are oppositely arranged on the upper side and the lower side of the eccentric wheel die body. The eccentric wheel die body which is eccentrically arranged enables a pipe to generate translational displacement in the bending radius direction when the pipe is bent, the stable forming requirement of a large-pipe-diameter carbon pipe and a large-section profiled bar is met, forward thrust can be generated through the active axial boosting effect of the auxiliary pushing and guiding die mechanism, and the problem that the wall thickness of the outer side of the pipe is reduced due to stretching is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of bending machine technology, and in particular to a pipe bending machine and bending method. Background Technology

[0002] Pipe bending machines are core equipment for achieving high-precision bending and forming of pipes. They are mainly used for bending and forming round pipes, square pipes, hollow pipes, solid pipes, and special-shaped pipes. Materials include carbon steel pipes, stainless steel, aluminum profiles, high-temperature alloys, and other non-ferrous metal pipes. They are widely used in aerospace, automotive, and engineering machinery industries.

[0003] Existing pipe bending machines typically include a bending mechanism and a bending die. The bending mechanism and the bending die are positioned opposite each other, and the pipe is clamped by the bending mechanism and the bending die. The bending mechanism and the bending die rotate synchronously around an axis to achieve bending of the pipe. They are also equipped with a mandrel mechanism, which prevents the inside of the cavity from collapsing during the bending process by inserting the mandrel into the cavity of the workpiece.

[0004] However, existing pipe bending machines only rotate around a single axis, meaning the bending mechanism and bending die rotate in a circle around the axis. The pipe can only perform pure bending motion without translational displacement along the bending radius. This makes it impossible to achieve stable forming of large-diameter carbon pipes and large-section profiles. Furthermore, during bending, the outer side of the pipe is subjected to tension and the inner side to compression, and the material cannot be dynamically compensated for according to deformation, resulting in excessive stretching and thinning on the outer side and instability and wrinkling on the inner side. In addition, existing mold cavities are mostly fixed, making loading and unloading operations difficult. Moreover, the pipe needs to be stretched during bending, which causes high friction with the mold and easily leads to surface scratches and damage. Summary of the Invention

[0005] To address the technical problem in the aforementioned background art that existing pipe bending machines only rotate around an axis, meaning the bending mechanism and bending die rotate in a circle around the axis, and the pipe can only perform pure bending motion without translational displacement along the bending radius, thus failing to achieve stable forming of large-diameter carbon pipes and large-section profiles, this invention provides a pipe bending machine and bending method.

[0006] The technical solution of this invention is as follows: This invention provides a pipe bending machine, including a machine body. A rotary motion mechanism is installed at the head of the machine body. The rotary motion mechanism is connected to a pipe bending eccentric mold and a clamping mold mechanism. The pipe bending eccentric mold and the clamping mold mechanism are arranged opposite to each other. An auxiliary push mold mechanism is provided on one side of the clamping mold mechanism. The clamping mold mechanism and the auxiliary push mold mechanism are arranged sequentially along the length of the machine body. The auxiliary push mold mechanism is used to actively axially push the workpiece to generate positive thrust and forcibly slow down the wall thickness reduction rate. The pipe bending eccentric mold includes an eccentric wheel mold body, which is an eccentric fan-shaped disk. The center position of the eccentric wheel mold body is offset from its rotation center. An upper wheel mold and a lower wheel mold are arranged opposite to each other on the upper and lower sides of the eccentric wheel mold body. The upper wheel mold and the lower wheel mold are used to clamp the workpiece. The rotary motion mechanism drives the eccentric bending die and clamping die mechanism to rotate synchronously, realizing the bending and forming of the pipe. The eccentrically set eccentric wheel die body allows the pipe to generate translational displacement along the bending radius during bending, breaking the limitation of single rotation around the axis. It is suitable for the stable forming requirements of large-diameter carbon pipes and large-section profiles. The clamping structure of the upper and lower wheel dies can reliably fix the pipe, ensuring the positional stability of the pipe during bending. The active axial push of the auxiliary pusher die mechanism can generate positive thrust, effectively alleviating the wall thickness reduction problem caused by stretching on the outside of the pipe, while improving the instability of the inside of the pipe under pressure. It realizes dynamic deformation compensation of the material during bending and improves the forming quality of the pipe bending.

[0007] Preferably, the lower die is fixedly connected to the eccentric die body, and several guide shafts are fixedly provided on the upper surface of the eccentric die body. The upper die is slidably connected to the guide shafts, and an opening and closing positioning block is fixedly installed on the top of the guide shaft. A pressing mechanism is fixedly installed on the eccentric die body, which is used to press and limit the upper die. The fixed setting of the lower die ensures the bottom support stability when the pipe is bent. The sliding cooperation between the upper die and the guide shaft makes the opening and closing operation of the die smooth, which can adapt to the clamping needs of pipes with different diameters and cross-sectional sizes, improving the adaptability of the equipment. The opening and closing positioning block can form a vertical limit on the sliding of the upper die, preventing the upper die from detaching from the guide shaft and ensuring the safety of the mechanism operation. The pressing mechanism can form a reliable pressing limit on the upper die after it has slid into place, allowing the upper die and the lower die to fit tightly against the pipe, avoiding the pipe from shifting or deviating during bending, and ensuring the firmness of the clamping. At the same time, the opening and closing structure of the die greatly reduces the difficulty of loading and unloading pipes and improves production efficiency.

[0008] Preferably, the pressing mechanism includes a bracket fixedly mounted on the upper surface of the eccentric wheel mold body. A pressing cylinder is fixedly mounted on the bracket, and a pressure block is slidably mounted on the bracket. The pressure block is fixedly connected to the telescopic end of the pressing cylinder. The pressure block is located above the upper wheel mold, and the top of the pressure block is hinged to the top of the bracket via a second connecting rod and a first connecting rod in sequence. The pressing mechanism, composed of the pressing cylinder, the connecting rod structure, and the pressure block, can convert the driving force of the cylinder into a stable downward pressing action. The connecting rod hinge structure can improve the smoothness and synchronization of the pressure block's movement, avoid uneven force caused by single-point pressure, and ensure that the upper wheel mold applies a uniform clamping force to the pipe, ensuring both clamping firmness and preventing deformation of the pipe surface due to excessive local pressure.

[0009] Preferably, a flexible protective layer is fixedly installed on the lower surface of the upper die and the upper surface of the lower die. This layer can isolate the die from direct hard contact with the pipe during clamping and bending, reduce the coefficient of friction between the two, and prevent defects such as tearing and scratches on the pipe surface. At the same time, the flexible layer can produce slight deformation to better fit the outer contour of the pipe, further improve clamping stability, and ensure the appearance quality and forming accuracy of the pipe.

[0010] Preferably, the clamping mold mechanism includes a bent arm, a first slide rail is fixedly provided on the upper surface of the bent arm, a first slide block is slidably provided on the first slide rail, the first slide block is connected to the clamping cylinder, and a copying mold is installed on the first slide block, so that the copying mold can flexibly adjust the clamping position according to the pipe specifications. The copying mold can conform to the outer contour of the pipe to achieve precise clamping, and maintain a stable clamping state during the rotation and bending process, preventing the pipe from slipping or shifting, and ensuring that the bending angle and forming size are accurately controllable.

[0011] Preferably, the auxiliary push-guide mold mechanism includes a second slide rail fixedly mounted on the machine body, extending towards the direction of the eccentric bending mold. A second slide block is slidably mounted on the second slide rail, and the second slide block is connected to a second servo motor via a first lead screw. A third slide rail and a third servo motor are fixedly mounted on the second slide block, extending towards the clamping mold mechanism. A copying guide mold is slidably mounted on the third slide rail, and the copying guide mold is connected to the third servo motor via a second lead screw. This allows for displacement adjustment of the copying guide mold in multiple directions, adjusting the boosting position and thrust magnitude according to the real-time bending state of the pipe, actively providing axial material compensation for the pipe, balancing the stress difference caused by tension on the outer side and compression on the inner side during bending, fundamentally reducing the problems of inner instability and wrinkling, and outer thinning due to stretching. Simultaneously, the servo drive has a fast response speed and high positioning accuracy, enabling high-precision synchronous coordination with the rotary bending action.

[0012] Preferably, a mandrel support mechanism is provided at the tail of the machine body. The mandrel support mechanism includes a mandrel-pulling cylinder. The telescopic end of the mandrel-pulling cylinder is connected to a first pull rod. The first pull rod is connected to several second pull rods through a distributor. The axes of the first pull rod and all the second pull rods are parallel. Each second pull rod is connected to a mandrel. A retaining seat is installed on the machine body to prevent misalignment of the second pull rods. This allows for simultaneous internal support of multi-cavity tubing, ensuring the synchronous movement of each mandrel and avoiding inconsistent telescopic movements. The retaining seat can limit and guide the second pull rods, preventing misalignment or swaying of the mandrels during telescopic movement. This ensures that the mandrels are accurately inserted into the workpiece cavity, effectively supporting the inner wall of the tubing, preventing cavity collapse and deformation during bending, and improving the forming quality of irregularly shaped tubing.

[0013] Preferably, a roller is provided at the machine head, and an end positioning mechanism is fixed on the front side of the roller. The roller can support and guide the pipe, reducing the shaking and friction of the pipe during the bending process. The end positioning mechanism can quickly define the axial installation position of the workpiece, realize the rapid and accurate positioning of the workpiece, save the time of repeated adjustment of alignment, improve the loading and unloading efficiency and processing positioning accuracy, and ensure that the bending start position of each workpiece is consistent.

[0014] A method for bypassing bends, comprising: The workpiece is placed between the upper and lower wheel molds, so that the end of the workpiece abuts against the end positioning mechanism; After the workpiece is placed in place, the clamping cylinder is activated, causing the copying mold to fit against the outer side of the workpiece and pushing the inner side of the workpiece to fit against the side wall of the eccentric wheel mold body. The pressing cylinder drives the pressure block to move downward, so that the upper wheel mold and the lower wheel mold clamp and fix the workpiece. After the eccentric bending mold and clamping mold mechanism have finished clamping the workpiece, the second servo motor is activated, so that the copying guide mold fits against the outer arc surface of the workpiece, and then the mandrel is installed in the corresponding cavity. The rotary motion mechanism is started, and the bending eccentric mold and the clamping mold mechanism rotate synchronously around the axis. The third servo motor starts synchronously, driving the copying guide mold to actively push along the third slide rail toward the clamping mold mechanism.

[0015] Through step-by-step, orderly actions of positioning, clamping, mold closing, pushing, and bending, the entire pipe processing process is standardized. The composite motion mode of eccentric mold and active pushing can meet the stable forming of large-diameter, large-section irregular pipes. The active axial pushing and internal mandrel support work together to dynamically compensate for the material required for pipe bending deformation, effectively controlling the problems of wall thickness reduction and internal wrinkling. The high degree of coordination among the actions can improve processing efficiency and operational safety while ensuring forming quality.

[0016] Preferably, after the workpiece has completed bending, the third servo motor first stops working, then the copying guide mold and copying clamping mold separate from the workpiece in sequence, and finally the pressure block releases its pressure on the upper wheel mold, releasing the workpiece and removing the bent workpiece. Unloading in the order of stopping the booster, releasing the clamping mold, and finally opening the mold reduces the risk of springback or deformation of the workpiece before it is fully shaped, ensuring dimensional accuracy and shape stability after bending. The step-by-step release method is orderly and avoids bumps or scratches on the workpiece surface. It also simplifies the unloading process, facilitating the quick removal of the finished workpiece and preparing it for the next processing step, thus improving the overall processing continuity.

[0017] As can be seen from the above technical solutions, the advantages of the present invention are: 1. The eccentrically positioned eccentric die body allows the tube to undergo translational displacement along the bending radius during bending, breaking the limitation of single rotation around the axis. This adapts to the stable forming requirements of large-diameter carbon tubes and large-section profiles. The clamping structure of the upper and lower dies provides reliable fixation for the tube, ensuring its positional stability during bending. The active axial thrust of the auxiliary guide die mechanism generates positive thrust, effectively alleviating the wall thickness reduction problem caused by stretching on the outer side of the tube. At the same time, it improves the instability under pressure on the inner side of the tube, achieving dynamic deformation compensation of the material during bending and improving the forming quality of the tube bending.

[0018] 2. The sliding fit between the upper die and the guide shaft ensures smooth opening and closing of the die, facilitating the loading and unloading of workpieces. Flexible protective layers are fixedly installed on the lower surface of the upper die and the upper surface of the lower die, which can isolate the die from direct hard contact with the pipe during clamping and bending, reduce the coefficient of friction between the two, and avoid defects such as scratches and pulls on the pipe surface. At the same time, the flexible layer can produce slight deformation, better conforming to the outer contour of the pipe, further improving clamping stability and ensuring the appearance quality and forming accuracy of the pipe. Attached Figure Description

[0019] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a front view structural schematic diagram of a pipe bending machine according to one or more embodiments of the present invention; Figure 2 This is a rear view structural schematic diagram of the pipe bending machine according to one or more embodiments of the present invention; Figure 3 This is a top view of the pipe bending machine according to one or more embodiments of the present invention. Figure 4 This is a schematic diagram of the left-side structure of the pipe bending machine according to one or more embodiments of the present invention; Figure 5 This is a right-side structural schematic diagram of the pipe bending machine according to one or more embodiments of the present invention; Figure 6 This is a schematic diagram of the surface profile of a workpiece according to one or more embodiments of the present invention; Figure 7 This is a schematic diagram of the rotary motion mechanism according to one or more embodiments of the present invention; The components represented by the various reference numerals in the diagram are: 1. Machine body; 2. Rotary motion mechanism; 21. First servo motor; 22. First reducer; 23. Driving spiral bevel gear; 24. First rotating shaft; 25. Driven spiral bevel gear; 26. First helical gear; 27. Second rotating shaft; 28. Second helical gear; 3. Pipe bending eccentric mold; 31. Eccentric wheel mold body; 32. Upper wheel mold; 33. Lower wheel mold; 34. Flexible protective layer; 35. Guide shaft; 36. Opening and closing positioning block; 37. Pressing mechanism; 371. Bracket; 372. Pressing cylinder; 373. First connecting rod; 374. Second connecting rod; 375. Pressure block; 4. Clamping mold mechanism; 41. Bent arm; 42. Clamping cylinder; 43. Copying mold; 44. First slide rail; 45. Mounting base; 46. Connecting screw; 47. First slide block; 5. Auxiliary push-guide mold mechanism; 51. Second servo motor; 52. Second reducer; 53. First lead screw; 54. Second slide rail; 55. Second slide block; 56. Third slide rail; 57. Third servo motor; 58. Second lead screw; 59. Copying guide mold; 6. Spindle support mechanism; 61. Third slide block; 62. Fourth servo motor; 63. Gear; 64. Rack; 65. Core-pulling cylinder; 66. Fourth slide rail; 67. First pull rod; 68. Distributor; 69. Holding seat; 610. Second pull rod; 611. Quick connector; 7. Workpiece; 8. Idler roller; 9. End positioning mechanism. Detailed Implementation

[0021] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0022] Example 1 In a typical embodiment of the present invention, such as Figures 1-7 As shown, a pipe bending machine is proposed, comprising: a machine body 1, a rotary motion mechanism 2, a pipe bending eccentric die 3, a clamping die mechanism 4, an auxiliary guide die mechanism 5, and a mandrel support mechanism 6. The rotary motion mechanism 2 is mounted on the machine body 1 and connected to the pipe bending eccentric die 3 and the clamping die mechanism 4 to drive the pipe bending eccentric die 3 and the clamping die mechanism 4 to rotate synchronously around an axis. The pipe bending eccentric die 3 and the clamping die mechanism 4 are arranged opposite to each other for clamping and bending the workpiece 7. The auxiliary guide die mechanism 5 is fixedly mounted on the machine body 1 and is located on one side of the clamping die mechanism 4. In the non-working state, it clamps... The clamping die mechanism 4 and the auxiliary pushing die mechanism 5 are arranged sequentially along the length of the machine body 1. During the bending process, the outer side of the pipe will be thinned due to tensile stress, while the inner side will be prone to wrinkling and thickening due to compressive stress. The auxiliary pushing die mechanism 5 is used for active axial push, that is, to actively push in the direction of the main clamp (the direction of the clamping die mechanism 4), to supplement the material in the bending area, fundamentally adjust the material flow and stress distribution, generate positive thrust, directly offset the tensile stress on the outer side, forcibly slow down the wall thickness reduction rate, and make the wall thickness distribution more uniform. The mandrel support mechanism 6 is used to insert the mandrel into the cavity of the workpiece 7 to prevent the cavity of the workpiece 7 from collapsing during the bending process.

[0023] The machine head is also provided with a support roller 8 and an end positioning mechanism 9. The support roller 8 is rotatably set at the machine head to support the workpiece 7 and prevent the workpiece 7 from being worn and damaged by the machine body 1. The end positioning mechanism 9 is fixedly set on the front side of the support roller 8 to abut against the end of the workpiece 7, thereby limiting the placement position of the workpiece 7 and ensuring the standardization of the processing position of the workpiece 7. In this embodiment, the end positioning mechanism 9 is a baffle structure.

[0024] It should be noted that the idler roller 8 and the end positioning mechanism 9 need to rotate synchronously with the bending eccentric mold 3 and the clamping mold mechanism 4 to change their positions.

[0025] The rotary motion mechanism 2 is located at the head of the machine body 1, such as... Figure 7As shown, the rotary motion mechanism 2 comprises a first servo motor 21, a first reducer 22, a driving helical bevel gear 23, a first rotating shaft 24, a driven helical bevel gear 25, a first helical gear 26, a second rotating shaft 27, and a second helical gear 28. The output end of the first servo motor 21 is fixedly connected to the input shaft of the first reducer 22, and the driving helical bevel gear 23 is fixedly mounted on the output shaft of the first reducer 22 to output power from the first reducer 22 to the driving helical bevel gear 23. The first reducer 22 is used to reduce the speed of the first servo motor 21 and amplify the torque. The first rotating shaft 24 is rotatably connected to the machine body 1 through ball bearings. The driven helical bevel gear 25 is coaxially fixed at the top end of the first rotating shaft 24, and the driven helical bevel gear 25 meshes with the driving helical bevel gear 23. The first helical gear is also fixed on the first rotating shaft 24. The first helical gear 26 has a gap between its circumferential teeth and the driving helical bevel gear 23. The driving helical bevel gear 23 achieves rotational transmission by meshing with the driven helical bevel gear 25, which is coaxial with the top of the first rotating shaft 24. The first rotating shaft 24 mainly plays the role of changing the shape structure of the gearbox, so that the gearbox fully meets the part processing shape requirements of the pipe bending machine, effectively reducing interference points, and also playing the role of speed reduction and torque increase. The second rotating shaft 27 is rotatably set inside the machine body 1. A large-module second helical gear 28 is coaxially fixed at the root of the second rotating shaft 27. The second helical gear 28 adopts a hardened tooth surface design. The second helical gear 28 meshes with the first helical gear 26 for transmission. The first rotating shaft 24 transmits transmission to the second helical gear 28 on the second rotating shaft 27 through the meshing of the first helical gear 26. The second helical gear 28 rotates coaxially with the second rotating shaft 27 for transmission.

[0026] The rotary motion mechanism 2 provides powerful, stable and controllable force, making it irreplaceable in processing irregularly shaped large cross-sections with large moments of inertia, thick walls, special high-strength materials, and bending applications requiring high precision and consistency. It is smooth, impact-free and vibration-free. At the moment of bending into place, the system can easily maintain pressure to ensure that the workpiece 7 is fully shaped under pressure, which is beneficial for controlling springback and ensuring shape stability.

[0027] The eccentric bending die 3 is fixedly connected to the second rotating shaft 27, thus rotating around the shaft along with the second rotating shaft 27. The eccentric bending die 3 includes an eccentric wheel die body 31, an upper wheel die 32, and a lower wheel die 33. The eccentric wheel die body 31 is an eccentric fan-shaped disk. The center position of the eccentric wheel die body 31 is offset from its rotation center by a set distance. The side of the eccentric wheel die body 31 that contacts the workpiece 7 is divided into a straight section and an arc section. The arc section is located behind the straight section. When the eccentric wheel die body 31 rotates around the rotation center, its center will simultaneously rotate and translate, thus synchronously realizing the rotation and translation required for bending the pipe, so as to meet the processing action requirements of the workpiece 7 with a large bending radius. The upper wheel die 32 and the lower wheel die 33 are installed opposite each other on the upper and lower sides of the eccentric wheel die body 31, and the upper wheel die 32 and the lower wheel die 33 are close to the clamping die mechanism 4. The upper wheel die 32 and the lower wheel die 33 are used to clamp the workpiece 7.

[0028] In this embodiment, both the upper wheel mold 32 and the lower wheel mold 33 include a straight section and an arc section. The lower wheel mold 33 is fixedly connected to the eccentric wheel mold body 31 by bolts. The upper wheel mold 32 is movably connected to the eccentric wheel mold body 31. The upper wheel mold 32 can move vertically to change the distance between it and the lower wheel mold 33, which facilitates loading and unloading. A pressing mechanism 37 is also fixedly installed on the eccentric wheel mold body 31 to press and limit the upper wheel mold 32, ensuring effective clamping of the workpiece 7.

[0029] Specifically, a plurality of guide shafts 35 are fixedly provided on the upper surface of the eccentric wheel mold body 31. The upper wheel mold 32 is slidably connected to the guide shafts 35, thereby guiding the vertical movement of the upper wheel mold 32 and preventing the upper wheel mold 32 from tilting during vertical movement. An opening and closing positioning block 36 is fixedly installed on the top of the guide shaft 35 to limit the vertical movement of the upper wheel mold 32 and prevent the upper wheel mold 32 from falling off the guide shaft 35. The pressing mechanism 37 includes a bracket 371, a pressing cylinder 372, a first connecting rod 373, a second connecting rod 374, and a pressing block 375. The bracket 371 is fixedly installed on the upper surface of the eccentric wheel mold body 31, and the pressing cylinder 372 is vertically fixedly installed on the bracket 371. The telescopic end of the pressing cylinder 372 faces downwards, and the pressing block 375 is located on the front side of the pressing cylinder 372 (i.e., the side close to the upper mold 32). The pressing block 375 is fixedly connected to the telescopic end of the pressing cylinder 372. At the same time, the pressing block 375 is also slidably connected to the bracket 371. The pressing cylinder 372 can control the vertical movement of the pressing block 375. The pressing block 375 is located above the upper mold 32 to press the upper mold 32. The top of the pressing block 375 is hinged to a second connecting rod 374, and the top of the bracket 371 is hinged to a first connecting rod 373. The bottom end of the first connecting rod 373 is also hinged to the top end of the second connecting rod 374, thus forming a force amplification structure. The pressing needs can be met without a large-sized pressing cylinder 372.

[0030] A flexible protective layer 34 is fixedly installed on the lower surface of the upper wheel mold 32 and the upper surface of the lower wheel mold 33. If a plywood board is pasted on it, the workpiece 7 will bend tightly against the wheel mold during the bending process. The upper and lower surfaces are already tightly hugged, ensuring that the workpiece 7 is clamped. At the same time, the plywood board is added to the contact surface between the upper and lower surfaces and the workpiece 7, which greatly avoids scratches on the workpiece 7.

[0031] The clamping mold mechanism 4 is fixedly connected to the second rotating shaft 27, thus rotating around the shaft following the second rotating shaft 27. The clamping mold mechanism 4 is arranged opposite to the bending eccentric mold 3, and can cooperate with the bending eccentric mold 3 to clamp the workpiece 7. The clamping mold mechanism 4 includes a bent arm 41, a clamping cylinder 42, a copying clamping mold 43, a first slide rail 44, a mounting base 45, a connecting screw 46, and a first slide block 47. The bent arm 41 is fixedly connected to the second rotating shaft 27 and rotates synchronously with the bending eccentric mold 3. The first slide rail 44 is fixedly installed on the upper surface of the bent arm 41 and extends toward the bending eccentric mold 3. The first slide block 47 is slidably connected to the first slide rail 44. The mounting base 45 is slidably disposed on the first slide block 47 and connected to the first slide block 47 by the connecting screw. 46 is connected to the first slide 47. The two ends of the connecting screw 46 are threaded to the mounting base 45 and the first slide 47 respectively to adjust the relative distance between the mounting base 45 and the first slide 47. The copying clamping mold 43 is fixedly installed on the mounting base 45, and the copying clamping mold 43 is set opposite to the straight section of the eccentric wheel mold body 31 to cooperate with the upper wheel mold 32 and the lower wheel mold 33 to clamp the workpiece 7. The clamping cylinder 42 is obliquely rotated and installed at the bottom of the bent arm 41, and the bent arm 41 is hinged to the first slide 47 through the connecting rod assembly to form a force amplification structure (the same as the connecting rod structure principle of the pressing mechanism 37). It can achieve great mechanical gain and clamping force without the need for a large-sized clamping cylinder 42, effectively preventing the workpiece 7 from slipping during bending.

[0032] The auxiliary push mold mechanism 5 is fixedly installed on the machine body 1 and located on one side of the clamping mold mechanism 4. The auxiliary push mold mechanism 5 is also set opposite to the bending eccentric mold 3 to assist in clamping and actively pushing the workpiece 7, supplementing material in the bending area, fundamentally adjusting the material flow and stress distribution, generating positive thrust, directly offsetting the tensile stress on the outside, forcibly slowing down the wall thickness reduction rate, and making the wall thickness distribution more uniform.

[0033] The auxiliary guide mold mechanism 5 includes a second servo motor 51, a second reducer 52, a first lead screw 53, a second slide rail 54, a second slide block 55, a third slide rail 56, a third servo motor 57, a second lead screw 58, and a contour guide mold 59. The second servo motor 51, the second reducer 52, and the second slide rail 54 are all fixedly mounted on the machine body 1. The second slide rail 54 extends toward the direction of the bending eccentric mold 3 and is parallel to the first slide rail 44 on the clamping mold mechanism 4 in the non-clamped state. The second slide block 55 is slidably mounted on the second slide rail 54. The second servo motor 51 is connected to the first lead screw 53 through the second reducer 52. The first lead screw 53 is threadedly connected to the second slide block 55, thereby driving the second slide block 55 to reciprocate along the second slide rail 54. The third slide rail 56 is fixed. The third slide rail 56 is arranged laterally on the second slide block 55 and perpendicular to the second slide rail 54, that is, the third slide rail 56 extends toward the clamping mold mechanism 4. The third servo motor 57 is fixedly installed on the second slide block 55 and is connected to the second lead screw 58, which is a ball screw. The second slide block 55 is provided with a nut. The third servo motor 57 synchronously drives the nut to rotate with a synchronous belt / gear. The nut meshes with the second lead screw 58 to control the axial movement of the second lead screw 58. The copying guide mold 59 is slidably arranged on the third slide rail 56. The copying guide mold 59 is arranged opposite to the arc segment of the eccentric wheel mold body 31, and the copying guide mold 59 is fixedly connected to one end of the second lead screw 58, so that it can follow the second lead screw 58 to move toward / away from the clamping mold mechanism 4.

[0034] The second servo motor 51 not only enables the copying guide mold 59 and the clamping mold mechanism 4 to hold the workpiece 7, but also allows the copying guide mold 59 to uniformly retract and unload during operation when the workpiece 7 is processed using an eccentric mold due to its large bending radius, thus perfectly coordinating the use of eccentric motion. The third servo motor 57 can control the copying guide mold 59 to actively push towards the clamping mold mechanism 4 during the processing of the workpiece 7, so as to supplement material in the bending area, fundamentally adjust the material flow and stress distribution, generate positive thrust, directly offset the tensile stress on the outside, forcibly slow down the wall thickness reduction rate, and make the wall thickness distribution more uniform.

[0035] This embodiment adopts a clamping mold and eccentric mold bending forming process. The profile is plastically formed in the mold cavity. The entire forming process adopts a servo system to compensate for the angle value according to the material characteristics. After the product is bent and formed, the product will be kept in the clamped state in the mold cavity. The product is held in the clamped state for 1-2 seconds to fully plastically form it, which makes it easy to control the springback and ensure the shape stability.

[0036] like Figure 6As shown, the upper and lower sides and the inner side of the workpiece 7 are all flat, and the outer side of the workpiece 7 is an arc surface. Correspondingly, the mold cavities of the copying clamping mold 43 and the copying guide mold 59 are arc surface structures that are adapted to the outer side of the workpiece 7.

[0037] The spindle support mechanism 6 is installed at the tail of the machine body 1. The spindle support mechanism 6 includes a third slide 61, a fourth servo motor 62, a gear 63, a rack 64, a core-pulling cylinder 65, a fourth slide rail 66, a first pull rod 67, a distributor 68, a retaining seat 69, a second pull rod 610, and a quick connector 611. The rack 64 and the fourth slide rail 66 are fixedly installed on the upper surface of the machine body 1, extending along the width direction of the machine body 1. A slider is fixedly provided at the bottom of the third slide 61, which slides on the fourth slide rail 66. The fourth servo motor 62 and the core-pulling cylinder 65 are both fixedly installed on the third slide 61. The gear 63 is fixedly installed on the output shaft of the fourth servo motor 62, and meshes with the rack 64. The fourth servo motor 62 can control the reciprocating movement of the third slide 61 along the fourth slide rail 66. The core-pulling cylinder 65 is arranged laterally, and the distributor 68 and the retaining seat 69 extend along the width direction of the machine body 1. The length direction of the core-pulling cylinder 65 is spaced apart, and the retaining seat 69 is fixedly installed on the machine body 1. The distributor 68 is close to the core-pulling cylinder 65. The telescopic end of the core-pulling cylinder 65 is connected to the distributor 68 through the first pull rod 67. The distributor 68 is used for the installation of multiple second pull rods 610. The distributor 68 is provided with several mounting holes, each mounting hole corresponding to one second pull rod 610. The diameter of the second pull rod 610 is smaller than that of the first pull rod 67. The retaining seat 69 is provided with several through holes to allow the second pull rods 610 to pass through and prevent the second pull rods 610 from being misaligned. The first pull rod 67 is parallel to the axis of all the second pull rods 610. Each second pull rod 610 is connected to a mandrel. Since the workpiece 7 has many cavities, multiple mandrels can meet the dimensional fullness and requirements of the product. The telescopic end of the core-pulling cylinder 65 and the end of the first pull rod 67 are connected by a quick connector 611 to realize quick assembly and disassembly between the core-pulling cylinder 65 and the first pull rod 67.

[0038] Example 2 Another typical embodiment of the present invention provides a bending bypass method, comprising: First, place the workpiece 7 between the upper wheel mold 32 and the lower wheel mold 33, so that the end of the workpiece 7 abuts against the end positioning mechanism 9; After the workpiece 7 is placed in place, the clamping cylinder 42 is activated, pushing the first slide block 47 to move along the first slide rail 44 toward the eccentric mold 3, so that the copying clamping mold 43 fits against the outer arc surface of the workpiece 7, and pushes the inner side of the workpiece 7 to fit against the edge side wall of the eccentric wheel mold body 31. Then, the pressing cylinder 372 drives the pressing block 375 to move downward, pressing the upper wheel mold 32, so that the upper wheel mold 32 and the lower wheel mold 33 clamp and fix the upper and lower surfaces (planar parts) of the workpiece 7, thus completing the clamping of the workpiece 7. After the bending eccentric mold 3 and the clamping mold mechanism 4 have finished clamping the workpiece 7, the second servo motor 51 is activated, driving the second slide block 55 to move along the second slide rail 54 toward the direction of approaching the workpiece 7, so that the copying guide mold 59 fits against the outer arc surface of the workpiece 7. Then, install the second tie rod 610 and the mandrel according to the number of cavities of the workpiece 7, connect the first tie rod 67 to the core-pulling cylinder 65, and install the mandrel in the corresponding cavity to prevent the cavity from collapsing during the bending process of the workpiece 7. The first servo motor 21 is started, which drives the bending eccentric mold 3 and the clamping mold mechanism 4 to rotate synchronously around the shaft through the second rotating shaft 27. During this period, the third servo motor 57 is started synchronously, which drives the copying guide mold 59 to actively push along the third slide rail 56 toward the clamping mold mechanism 4 (which can also be understood as the direction of the machine head) through the second lead screw 58. This is to supplement the material in the bending area, fundamentally adjust the material flow and stress distribution, generate positive thrust, directly offset the tensile stress on the outside, forcibly slow down the wall thickness reduction rate, and make the wall thickness distribution more uniform. After the above actions, the workpiece 7 completes the bending. First, the third servo motor 57 stops working, and the second servo motor 51 drives the second slide block 55 to move backward, so that the copying guide mold 59 separates from the workpiece 7. Then, the clamping cylinder 42 retracts, so that the copying clamping mold 43 moves backward and separates from the workpiece 7. Finally, the pressing cylinder 372 drives the pressure block 375 to move upward, canceling the pressing on the upper wheel mold 32, releasing the workpiece 7, and the bent workpiece 7 is manually removed.

[0039] Understandably, before processing the next workpiece 7, the rotary motion mechanism 2 needs to drive the bending eccentric mold 3 and the clamping mold mechanism 4 to rotate and reset. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pipe bending machine, comprising: The machine body (1) is equipped with a rotary motion mechanism (2) at the machine head. The rotary motion mechanism (2) is connected to a pipe bending eccentric mold (3) and a clamping mold mechanism (4). The pipe bending eccentric mold (3) and the clamping mold mechanism (4) are arranged opposite to each other. An auxiliary push mold mechanism (5) is provided on one side of the clamping mold mechanism (4). The clamping mold mechanism (4) and the auxiliary push mold mechanism (5) are arranged sequentially along the length direction of the machine body (1). The auxiliary push mold mechanism (5) is used to actively axially push the workpiece (7) to generate positive thrust and forcibly reduce the wall thickness reduction rate. The eccentric mold for bending pipe (3) includes an eccentric wheel mold body (31), which is an eccentric fan-shaped disk. The center position of the eccentric wheel mold body (31) is offset from its rotation center. The upper wheel mold (32) and the lower wheel mold (33) are provided on the upper and lower sides of the eccentric wheel mold body (31). The upper wheel mold (32) and the lower wheel mold (33) are used for clamping the workpiece (7).

2. The pipe bending machine according to claim 1, characterized in that, The lower wheel mold (33) is fixedly connected to the eccentric wheel mold body (31). Several guide shafts (35) are fixedly provided on the upper surface of the eccentric wheel mold body (31). The upper wheel mold (32) is slidably connected to the guide shafts (35). An opening and closing positioning block (36) is fixedly installed on the top of the guide shafts (35). A pressing mechanism (37) is fixedly installed on the eccentric wheel mold body (31). The pressing mechanism (37) is used to press and limit the upper wheel mold (32).

3. The pipe bending machine according to claim 2, characterized in that, The pressing mechanism (37) includes a bracket (371) fixedly installed on the upper surface of the eccentric wheel mold body (31), a pressing cylinder (372) fixedly installed on the bracket (371), a pressing block (375) slidably provided on the bracket (371), the pressing block (375) is fixedly connected to the telescopic end of the pressing cylinder (372), the pressing block (375) is located above the upper wheel mold (32), and the top of the pressing block (375) is hinged to the top of the bracket (371) in sequence through the second connecting rod (374) and the first connecting rod (373).

4. The pipe bending machine according to claim 2, characterized in that, A flexible protective layer (34) is fixedly installed on the lower surface of the upper wheel mold (32) and the upper surface of the lower wheel mold (33).

5. The pipe bending machine according to claim 3, characterized in that, The clamping mold mechanism (4) includes a bent arm (41), a first slide rail (44) is fixedly provided on the upper surface of the bent arm (41), a first slide block (47) is slidably provided on the first slide rail (44), the first slide block (47) is connected to the clamping cylinder (42), and a copying clamping mold (43) is installed on the first slide block (47).

6. The pipe bending machine according to claim 5, characterized in that, The auxiliary push-guide mold mechanism (5) includes a second slide rail (54) fixedly mounted on the machine body (1). The second slide rail (54) extends toward the direction of the bending pipe eccentric mold (3). A second slide block (55) is slidably mounted on the second slide rail (54). The second slide block (55) is connected to the second servo motor (51) through the first lead screw (53). A third slide rail (56) and a third servo motor (57) are fixedly mounted on the second slide block (55). The third slide rail (56) extends toward the direction of the clamping mold mechanism (4). A copying guide mold (59) is slidably mounted on the third slide rail (56). The copying guide mold (59) is connected to the third servo motor (57) through the second lead screw (58).

7. The pipe bending machine according to claim 5, characterized in that, The tail of the machine body (1) is provided with a spindle support mechanism (6). The spindle support mechanism (6) includes a core-pulling cylinder (65). The telescopic end of the core-pulling cylinder (65) is connected to a first pull rod (67). The first pull rod (67) is connected to several second pull rods (610) through a distributor (68). The first pull rod (67) is parallel to the axis of all the second pull rods (610). Each second pull rod (610) is connected to a core rod. The machine body (1) is provided with a retaining seat (69) to prevent the second pull rods (610) from being misaligned.

8. The pipe bending machine according to claim 5, characterized in that, A roller (8) is provided at the head of the machine for rotation, and an end positioning mechanism (9) is fixed on the front side of the roller (8).

9. A method for bypassing bends, characterized in that, The pipe bending machine used as described in any one of claims 5-8 includes: Place the workpiece (7) between the upper wheel mold (32) and the lower wheel mold (33) so that the end of the workpiece (7) abuts against the end positioning mechanism (9); After the workpiece (7) is placed in place, the clamping cylinder (42) is activated, so that the copying mold (43) fits against the outer side of the workpiece (7), and pushes the inner side of the workpiece (7) to fit against the side wall of the eccentric wheel mold body (31). The pressing cylinder (372) drives the pressure block (375) to move downward, so that the upper wheel mold (32) and the lower wheel mold (33) clamp and fix the workpiece (7). After the bending eccentric mold (3) and clamping mold mechanism (4) have finished clamping the workpiece (7), the second servo motor (51) is activated, so that the copying guide mold (59) fits against the outer arc surface of the workpiece (7), and then the mandrel is installed in the corresponding cavity. Start the rotary motion mechanism (2), the bending eccentric mold (3) and the clamping mold mechanism (4) rotate synchronously around the axis, the third servo motor (57) starts synchronously, and drives the contour guide mold (59) to actively push along the third slide rail (56) toward the clamping mold mechanism (4).

10. The bending method according to claim 9, characterized in that, After the workpiece (7) has completed its bend, the third servo motor (57) stops working, and then the copying guide mold (59) and copying clamping mold (43) separate from the workpiece (7) in sequence. Finally, the pressure block (375) releases the pressure on the upper wheel mold (32), releases the workpiece (7), and removes the workpiece (7) after it has completed its bend.

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